1. Field of the Invention
The present invention relates to a method and an apparatus for suspending a chain of linked products such as sausages in which a material such as meat is stuffed in a casing.
2. Description of the Related Art
A chain of linked products stuffed with a material is subjected to heat processing or other similar processing in an ensuing process, depending on the material. For this reason, the chain of product is suspended from a bar-like member commonly called a smoking stick in a series of loops and are brought into a heat treatment chamber. In order to allow the series of loops to be suspended from the smoking stick, the chain of linked products is conventionally suspended consecutively in the form of loops from a plurality of suspending members that are moving. After the smoking stick is inserted through the loops, the smoking stick is lifted up so as to transfer the series of loops onto the smoking stick.
Two types of apparatus are conventionally known as the apparatus for suspending loops.
First, the following apparatus is known as the first type. A mainly tubular guide member for guiding the chain of linked products is connected to a downstream end of a conveying device for conveying the chain of linked products. The chain of linked products is released into an open space while a release outlet of the guide member is being eccentrically rotated or being swung. Hook-like suspending members disposed at predetermined intervals on an endlessly traveling member are made to travel along a path intersecting to the movement of the released chain of linked products so as to consecutively retain the chain of linked products by the suspending members, thereby forming loops. With an apparatus of the above-described type, the conveying device and a suspending device are interlocked by means of chain transmission in such a manner that the operation of the guide member and the movement of the suspending members are synchronized at a retaining position. Then, each length of the chain of linked products to be suspended can be selected by changing the ratio of the number of teeth of respective sprockets of the conveying device and the suspending device in the chain transmission. Apparatuses of the above-described type are disclosed in Japanese Patent Publication No. 5899/1966 (U.S. Pat. No. 3,191,222), Japanese Utility Model Laid-Open No. 1594/1975, Japanese Patent Publication No. 26084/1980 (U.S. Pat. No. 3,964,129), and Japanese Patent Publication No. 13329/1989 (U.S. Pat. No. 4,539,796), and the like.
Next, as the second type, an apparatus is known in which the number of links of the chain of linked products passing through a fixed point in the conveying device is detected, whereby the movement of the endlessly traveling member of the suspending device is controlled. Apparatuses of this type are disclosed in Japanese Patent Publication Nos. 43210/1982 and 27023/1986 (U.S. Pat. No. 4,218,003). With these apparatuses, a contact finger is brought into direct contact with the chain of linked products being conveyed, so as to detect the links.
With the above-described conventional apparatuses, the following drawbacks have been encountered.
First, with the apparatus of the first type, when it is desirous to change the length of the link of the chain of linked products or the suspension length (the size of the loop), it is necessary to change the ratio of the number of teeth of the sprockets because of chain transmission. For that reason, it is necessary to replace the sprockets to those having different numbers of teeth and the chain to one having a length corresponding to the same. Hence, replacement requires time and trouble, and the apparatus is shut down during that time, causing a decline in the operating ratio. In addition, different sprockets and chains must be stocked, which increases the cost.
Meanwhile, with the apparatus of the second type, since there are no component parts which require replacement, such as sprockets, the change of the link length and the size of the loop is conducted simply.
With the apparatus of this type, however, since the contact finger is brought into direct contact with the links of the chain of linked products in the conveying device, detection errors are apt to occur owing to the non-uniformity of the shape and hardness of the product, stains attached to the surface, and water used in the apparatus, and the like. In addition, even if the detection is carried out on a non-contact basis, these detection errors cannot be avoided insofar as the links are detected. If such detection errors occur, it becomes impossible to form desired loops. Furthermore, since detection errors are apt to occur, this arrangement is unsuitable for high-speed operations with increased conveying speed.